As rumored, Apple has introduced the fruits of its voice-based artificial intelligence business, Siri acquisition. As expected Siri now comes built into iPhone 4S, bringing advanced voice control to this handset.

“Siri is your intelligent assistant that helps you get things done just by asking”, says the official tagline. Siri lets you interact with your device much as you would with your personal assistant; you can talk to your phone and it’ll respond as personal assistant.

During the “Let’s Talk iPhone” event, Apple demonstrated different ways of talking to your iPhone, and Siri responded just like a real personal assistant. Apple’s Scott Forstall took us through setting up alarm, weather forecast, asking the current time in Paris, finding a restaurant and even setting up a meeting using just the power of natural voice commands. Siri will also read your text and email messages to you.

Siri also features results from Wolfram Alpha and Wikipedia. Using hands-free technology, users can now ask the iPhone real questions, with the answer being returned via the relevant source. User can also dictate using a microphone button available on the keyboard.

You can activate Siri just by holding down the home button briefly and it understands natural-language queries in English, German and French, more languages coming soon.

Siri, the personal assistant feature is an iPhone 4S feature only and will become available to the masses when iOS 5 launches on October 12th.

Siri examples

Scott Forstall: “What is the weather like today?”
Siri: “Here is the forecast for today.”
Scott Forstall: “Do I need a raincoat today?”
Siri: “It sure looks like rain today”
Scott Forstall: “Find me a great Greek restaurant in Palo Alto.” You get results from Yelp sorted by rating.